Process of activating or revivifying finely divided materials



Patented Apr. 5, 1932 UNITED STATES PATENT OFFI GEORGE GLEN BROCKWA'Y FWARREN, PENNSYLVANIA, ASSIGNOR, BY MESNE AS- SIGNMENTS, TO NICHOLSENGINEERING AND .RESEARCH YORK, N. Y., A CORPORATION OF DELAWARECORPORATION, OF NEW rnoonss or aorrva'rmc on rmvrvrrrmc FINELY mvrnnnmisnnms No Drawing. Continuation or application Serial No. 290,791,filed. July 5, 1928. This application illod October 16, Q28. Serial No.312,938.

This invention relates to methods or processes of activating orrevivifying finely divided materials, such for example as natural oractivated clay or earth materials used as 5 filtering, decolorizingand'purifying agents in the refining of various kinds of animal,vegetable and mineral oils, fats, waxes and greases.

Until recent times petroleum refiners have 0 been treating oils by firstdistilling and then treating the various fractions with acid,neutralizing with caustic-materials, and filtering by percolationthrough large bodies of coarse fullers earth, for example either 16-30or 5 -60 mesh. After a certain quantity of oil has been filtered throughthe percolator, which is usually a large tank containing many tons ofcoarse mesh earth, a solvent or distillate is run through the percolatorto re- 20 move the retained oil from the fullers earth.

JO oil to neutralize the free fatty acids, then bleaching and purifyingthe oil with fine fullers earth, generally of a 200 mesh. That is, thegreater percentage of the earth will pass through a 200 mesh screen.This latter operation is carried out by the so-called contact filtrationmethod, which consists in mixing a small quantity of refined earth withthe oil in a tank 'and agitating the mixture by mechanical means orotherwise, then filtering the oil through any suitable well known typeof filter press. The filter press cake, so-called', or earth,'which isremoved from the filter press, contains usually large percentages of oilby Weight of the cake. Heretofore it has been the practice to throw awaythis earth when the presses are cleaned, no method hav-.

ing been heretofore developed to successfully reactivate such fineearth.

Coarse or granular clays, after being used for filtering. as abovestated, may be reactivated according to Well known processes by theproper application of heat with admixture of air for the purpose ofdecarbonizing and destroying the impurities andcoloring matter whichhave been absorbed from the oil. This decarbonizing action is performedafter the larger portion of reta ned oil has been removed fromthe'earth. However, in attempting to reactivate either finely dividednatural or treated clays, the particles lie so close together that it isnot possible to admit in a proper mixture the amount of air which isnecessary for the complete oxidizing or decarbonizing action, and alsothe particles nearest the source of heat protect the underlyingparticles so as to prevent the heat and air from properly and uniformlyactin The objects of this invention inclu e the provision of adependable, convenient and s mple process or method for activating orrevivifying finely divided 'materials of the above indicated character.Further objects, features and advantages will more clearly appear fromthe detailed description given below and describing by way of examplecertain embodiments of the invention, the invenesses hereinafter setforth.

I have discovered a process according to tion consisting in the novelsteps and procv may be treated'to restore therein a degree of efiiciencycomparable to the results secured in revivifying coarse fullers earth.Accofd i ing to this process, I preferably first extract to be treated.This may be done by any suit able well known method either mechanicallyor by the use of solvents. Certain solvents may even be used which willpermit recovery of a high grade of'oil from this filter. cake which hasbeen heretofore thrown away or from which merely oil of low quality hasbeen recoverable. After the retained oil has been thus largely removed,according to my process, I mix with the fullers earth fines a suitablequantity of coarse material, for example an equal quantity of coarsefullers earth which has been used in percolatiori filtering methods,that is, 16-30 mesh or 30-60 mesh earth. It is advantageous to use suchso-called granular earth or earth which has been used in percolatingprocesses, since this material is usually readily available atrefineries for the reason that the, general practice heretofore has beento use the percolation filtering method,

However, it will be understood that in addition" to coarse mesh earth,either new or spent, various other materials may be equally well used,either separately or in mixtures, such for example as carefully washedand graded sand, quartz, or carborundum. The granular clay or othercoarse material is preferably thoroughly mixed with the finely divideddecolorizing material which is to be treated and although theproportions of different kinds of earths may be widely varied, I findthat in general substan- 'tially equal quantities of the coarse and finematerials may be mixed with satisfactory results as above stated.

This mixture of coarse and fine material is then heated in a properlyconstructed furnace, preferably of the well known multiple hearth typeshown in various patents to Herreshoff and in improvement patentsrelating to such type. A furnace of this type, having from 8 to 12 ormore hearths, has been found to be satisfactory for this purpose. Thetemperature maintained within the furnace may vary within rather widelimits, but I have found that temperatures from 800 vF.

' to 1150 F. give highly satisfactory results with a relatively lowconsumption of fuel. The amount of fuel used will of course vary withthe degree with which the oil residue has been previously extracted fromthe filter cake or earth and also with the character and quantity ofimpurities, particularly impurities embodying carbon, which have beenabsorbed from the oil. If a considerable amount of oil and carbonimpurities remain in the earth, this may serve to provide suflicientfuel or nearly enough fuel to properly maintain the decarbonizing actionwithout introducing additional fuel. The process may be carried oncontinuously within the furnace, the earth being rabbled over thehearths at a rate such that from in the neighborhood of three to fourhours are required for a given body of earth to travel down through thefurnace. However, this time may vary widely.

the body of material when the material is suitably rabbhfi. With theresulting exposure of all of the fine particles to the heated air, thefine earth is thoroughly decarbonized and the impurities which have beenabsorbed therein during the filtration of oil, as well as any inherentimpurities, are destroyed and the efliciency of the used earth isrestored to a degree approaching its initial efficiency. In fact thisrevivification operation may be repeated a large number of times withoutany substantial diminution of the efliciency of the earth beyond thatoccurring during the initial use and treatment thereof.

After the mixture of coarse and fine material is delivered from thefurnace, it is preferably passed through a suitable separating device toseparate the coarse material from the fine. The fine material is thenready to be reused, and if the coarse material used was granulatedfullers earth or the like material, this also will be revivified andwill now be ready for reuse.

Although in the above described example, the process is particularlyapplied to the treatment, of used fine earth, I have discovered that newfine fullers earth may likewise be treated in a similar manner by mixingthe coarse earth with the fines and the result in many cases is a greatimprovement in the filtering characteristics of such new fines. Suchtreatment of new fines may be carried out either at the location wherethe fullers earth is produced or at the oil refineries. Although all newfine earths apparently do not react uniformly to such treatment, I, havefound for example that certain so-called natural acid fine earths show aquite remarkable improvement under such treatment.

I also find it desirable in many instances to rehydrate the new or usedfine earths which have been treated according to the above describedprocess. In the contact method of filtration, moisture generally has abeneficial effect if present in fullers earth. This is believed to befor the reason that since the oil being treated is maintained at acomparative- 1y high temperature, the steam resulting Ibo from themoisture present serves to protect the oil from oxidation during thecontacting period. One commercial form of fine fullers earth, for.example, embodies approximately for example, the desired amount of watermay be added to the earth in bulk or as a spray while the earth isagitated in a mixer, or if this is found to be difficult for mechanicalreasons, the 011 which is being treated may be emulsified with theproper amount of water. y

In reactivating used fine earth even after the larger portion of the oilhas been extracted therefrom, there is a tendency for considerable freeburning of the remaining oil residue or gases contained therein,particularly on the upper hearths of the furnace. This renders itdiln'cult to control temperatures and to insure proper burning orroasting conditions. However, by mixing the coarse material with thefine earth, I find that this tendency for free burning is reducedsubstantially to a minimum or entirely avoided.

Dust losses are also minimized. By the use of this process 'there isapparently a very uniform absorption of heat throughout the mass ofmaterial which prevents the destruction of the fine earth from causessuch as sintering, glazing or fusing, which in the absence of the coarsematerial will take place at the hearth areas which are more exposed tothe source of heat.

This application comprises a continuation of my copending applicationSerial No. 290,- 701, filed-July 5,1928.

'While the invention has been described in detail with respect toparticular preferred examples thereof which give satisfactory results,it will be understood by those skilled in the art after understandingthe invention, that various changes and modifications may be madewithout departing from the spirit and scope of the invention and it isintended therefore in the appended claims to cover all such changes andmodifications.

What is claimed as new and desired to be secured by Letters Patent ofthe United States is:

1. Method of revivifying or reactivating spent fine filtering, oildecolorizing and purifying materials, which consists in first removingthe greater portion of any retained oil therefrom, mixing the materialwith a substantial quantity of relatively coarser or granular material,then treating the mixture in a furnace to substantially decarbonize thefine material, and finally removing said coarses or granular materialfrom the mixture.

2. Method of revivifying or reactivating spent fine filtering, oildecolorizing and purifying materials, which consists in mixing thematerial with a substantial quantity of relatively coarser or granularmaterial. then treating the mixture in a furnace to substantiallydecarbonize the fine material, and finally removing said coarser orgranular material from the mixture.

'3. Method of revlvifymg or reactivatmg spent. fine filtering, oildecolorizing and purifying materials, which consists in mixing thematerial with a substantial quantity of relaxv tively coarser orgranular material, and then treatin the mixture in a furnacetdsubstantially ecarbonize the fine material.

4. Method of revivifying or reactivating spent fine filtering, oildecolorizing and purifying materials, whichconsists in first removmg thegreater portion of any retained comprises mixing therewith approximatelyan equal quantity of a relatively much coarser material, and thentreating the mixture in a furnace to substantially, decarbonize the finematerial.

6. The method of revivifying fine fullers earth or the like materialwhich has been used in the contact process of oil filtration, whichcomprises mixing therewith a quantity of granular fullers earth derivedfrom the percolation process of oil filtration, and then substantiallydecarbonizing the mixture in a roasting furnace.

7. The method of revivifying fine fullers earth or the like materialwhich has bee used in the contact process of oil filtration, whichcomprises mixing therewith a quantity of granular fullers earth derivedfrom the percolation process of oil filtration, then substantiallydecarbonizing the mixture in a roasting furnace, and finally separatingthe fine and granular earths.

8. The method of revivifying fine fullers earth or the like -materialwhich has been used in the contact process of oil filtration, whichcomprises mixing therewith an approximately equal quantity of granularfullers earth derived from the percolation process of oil filtration,and then substantially decarbonizing the mixture in a roasting furnace.

9. The process of fullers earth revivification which comprises roastinga mixture of the fine and granular earths in discreet or separatedcondition, in the presence of an abundance of air, with agitation.

10. The process of fullers earth revivification which comprises roastinga mixture of the fine and granular earths, in the prese'nce of anabundance of air, with agitation, and at a temperature in theneighborhood of from 800 F. to 1150 F.

11. The process of fullers earth revivification which comprises mixingearths derived from contact and percolation oil filtration processes,roasting the mixture in the presence of an abundance of air, withagitation, and then separating said earths.

12. The process of treating fullers earth, which comprises roasting amixture of the relatively fine and granular earths in the presence of anabundance of air with agitation, and at a temperature in theneighborhood of from 800 F. to 1150 F.

13. Theprocess of treating fullers earth fines such as may be used inthe contact process of oil filtration, which comprises mixing such fineearth with relatively coarser or granular fullers earth, roasting themixture in the presence of an abundance of air with agitation. and thenseparating said earths.

14. Method of treating fine filtering, oil decolorizing, and purifyingmaterials, which comprises mixing the material with a substantialquantity of relatively coarser or granular material, then roasting themixture in a furnace, removing said coarser or granular material fromthe mixture, and restoring a quantity of moisture to the fine material.

15. Method of revivifying or reactivating spent fine filtering, oildecolorizing and purifying materials, which consists in first removingthe greater portion of any retained oil therefrom, mixing the materialwith a substantial quantity of relatively coarser or granular material,then treating the mixture in a furnace to substantially decarbonize thefine material, and thereafter uniformly mixing a limited amount ofmoisture in the material.

fines such as may be used in the contact process of oil filtration,which comprises mixing such fine earth with relatively coarser orgranular fullers earth, roasting the mixture in the presence of anabundance of air with agitation, separating said earths, and adding inthe neighborhood of 10% of moisture to said fines. v

17. The method of revivifying fine fullers earth or the like material,which has been used in the contact process of oil filtration, whichcomprises substantially decarbonizing the same while the particlesthereof are in dry, discreet or separated condition in a roastingfurnace, and then adding and unifOlllIllly mixing a quantity of moisturetherewit earth or the like material which has been used in the contactprocess of oil filtration, which comprises substantially decarbonizingthe same while the particles are in dry, diserect or separated conditionin a roasting furnace, and then restoring thereto a quantity of moistureat least substantially equal to the amount originally carried by theearth. 19. The process of treating fullers earth which comprisesroasting a mixture of fine earth having a particle size of upwards of 60mesh with earth having a particle size of up- 18. The method ofrevivifying fine fullers which comprises roasting a mixture of dry fineearth with a dry relatively coarse earth of which the particles are indiscreet or separated condition, in the presence of an abundance of air,with agitation.

In testimony whereof I have signed my name to this specification.

GEORGE GLEN BROCKWAY.

llvl

